There are many constructions in which two or more members must be secured to one another in a simple and reliable manner. Examples of such constructions are shelving systems, frameworks for display and other cabinets and partition systems.
Many proposals have been made which involve the use of a pair of locking arms which are received within the hollow interior of one of the members to be joined. The arms protrude from one end of said one member and the protruding portions of the arms are entered in an aperture or slot in the wall of the other member. The protruding portions each have an outwardly directed tooth thereon. The protruding portions are forced apart so that they engage with the wall parts which bound the slot, the teeth hooking behind said wall parts to prevent the protruding portions being withdrawn from the slot or aperture. In many forms, screws are employed to force the arms apart so that the protruding portions engage said wall parts.
In a structure developed by applicant, the arms are of elongate form with curved surfaces at each end. The arms are presented to the slot or aperture in a diverging relationship, the arms touching at one end and being spaced apart at the other. It is the touching ends of the arms which are presented to and enter the slot or aperture. When the spaced ends are sqeezed together, said surfaces of the arms at said one end roll on one another and said portions move apart into engagement with said wall parts. Such rolling action continues until the arms are parallel and back-to-back. Said one member, which is hollow, is then slid over the arms to hold them in their parallel relationship.
It is sometimes desirable to be able to connect together three members, two of the members being spaced apart, and the third member spanning the gap between these two members. In structures of the form described above, this would be achieved by using two pairs of arms, each pair connecting the third member to a respective one of the other members.